Hardwired control unit:
It is a unit that uses combinational logic units featuring a finite number of gates that can generate specific results, based on instructions that were used to invoke those responses. The speed of the operation is fast. Here, for the modification, the entire unit should be redesigned. They are more costly to implement. It is difficult to handle complex instructions. It is difficult to perform information Decoding. They use a small instruction set. There is no control memory usage. They are used in processors that use a simple instruction set known as the reduced instruction set computers(RISC). They are not flexible. Here, the sequential circuit is used. Here, The designing process is complicated. Micro programmed control unit:
It is a unit that contains microinstructions in the control memory to produce control signals. The speed of operation is slow because it requires frequent memory access. Here, modifications can be implemented by changing the microinstructions in the control memory. They are less costly to implement. It is easier to handle complex instructions. It is less difficult to perform information Decoding. They use a large instruction set. They use control memory. They are used in processors based on complex instructions set known as complex instruction set computers(CISC). They are flexible. Here, a programming circuit is used. Here, The designing process is systematic.